A large number of different types of automation equipment are previously known in this art which are employed for transporting a workpiece under processing in a press line from the die, or tool, in one press to the tool in the next press in the press line. This automation equipment is sited in the spaces between adjacent presses and must be moved aside when a truck or rail-borne carriage which is used for transporting the heavy tool on tool change is to be moved into the region between adjacent presses. The displacement of the transport equipment is often difficult to carry out because of lack of space.
One aggravating factor in connection with tool change according to conventional technology often resides in the fact that the available space surrounding the press line may be extremely limited so that not even displacement of the automation equipment can be put into effect in a simple manner. In addition, the area around the press line is often cluttered with, for example, workbenches, material stockpiles, tool cabinets, safety barriers and similar objects. As a result of the lack of space, manual adjustment work is impeded if not rendered wholly impossible.
Employing prior art conventional technology, the time-loss for tool change is so great that such a press line can hardly be competitive when the requirements on steadily shorter production series become more and more accentuated.
Presses of the "sliding bolster" type are also previously known in the art, in which the tools may be displaced laterally, transversely of the material flow direction, through an opening in the side of the press so that, thereby, the space between adjacent presses need not be taken up in tool change. Presses of this type per se provide for rapid tool change and have high output capacity, but are extremely capital-intensive. One example of a press of this type is described in U.S. Pat. No. 3,455,141.
Presses of the "transfer press" type are also previously known. In this press type, use is made of a plurality of tools in one and the same press. A press of this type makes for rapid tool change and possesses high capacity but, also in this case, the costs involved are prohibitively high. One example of such a press is described in GB-A-2,199,524.
U.S. Pat. No. 3,516,277 discloses a proposed solution to the problem partly of how transport of workpieces between adjacent presses may be put into effect, and partly how tool changes may be carried out with the aid of a carriage movable transversely of the material flow direction of the press.
The design and construction according to this publication entail that the transport equipment is mounted on a separate wheel-borne carriage between adjacent presses, the carriage being interconnected, via connection rods, to that carriage which is employed for transport of dies or tools transversely of the material flow direction of the press line and also being positively displaceable under the action of movement of this latter carriage. The construction according to this publication also includes a drive unit which is housed in the bedplate or floor and is employed to set the tool change carriage in motion.
In practice, the design and construction according to this patent specification are hardly feasible, since they fail to solve the problem inherent in the often extremely limited space surrounding the press line and in between adjacent presses. The pair of carriages together with their connection rods gives a structural dimension transversely of the material flow direction of the press line which, in most cases, is too large for the available space most proximal the longitudinal wall of the press hall. As a decisive disadvantage, mention must also be made of the drive unit housed in the bedplate or floor for the tool change carriage, which implies that the floor space between adjacent presses is not freely accessible for adjustment work, service and the like.